Hello. I was reading about Sonic and Knuckles on Wikipedia, click "Here" to read about it. Wikipedia told me there is a Sonic The Hedgehog ROMHack named Knuckles The Echidna In Sonic The Hedgehog. The ROMHack is made exactly like Sega would have made it if Knuckles was in Sonic The Hedgehog, it even allows you to become "Super Knuckles" once you have all the Emeralds. For Site rules and legal reasons I can't give you the direct link, to download this ROMHack just go to Google and type in Knuckles The Echidna In Sonic The Hedgehog and choose the first link.